Granite Falls

Old Rock

Along the Minnesota River, just past Granite Falls, and next door to the Yellow Medicine County Historical Museum, is (was) the world’s oldest exposed rock. At 3.8 billion years old, the rock was exposed when Glacial Lake Agassiz emptied into the ocean during the last Ice Age.

Some zircon crystals from the Jack Hills in Australia have recently been dated at 4.4 billion years old.

About icefogger

Just a basic, down to Earth, laid back type of guy here, who loves the outdoors, the indoors, jazz on the turntable, a fire in the woodstove, the northern lights blazing across the sky, and the company of good friends. View all posts by icefogger

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